Rabbit shank and foot
Photo and text: Margaret Woods
Lateral view of the rabbit's right shank and foot; anterior (craniad) is to the top of the photo and distal is to the right.
| Muscle | Origin | Insertion | Action |
| Extensors | |||
| Tibialis anterior | lateral condyle of the tibia | by a tendon onto the base of the second metacarpal | dorsiflexes ankle; inverts foot |
| Extensor digitorum longus | lateral patellar surface of the femur | by tendons onto all phalanges of the digits | extends second through fifth digits and dorsiflexes ankle |
| Peroneus muscles | |||
| Peroneus longus | lateral condyle of the tibia and the head of the fibula | by a tendon onto the end of the reduced first metatarsal | plantarflexes ankle; everts foot |
| This muscle's tendons travels down the lateral surface of the leg and under the foot across the plantar surface of the foot to reach its insertion. | |||
| Peroneus brevis | lateral condyle of the tibia | by a tendon onto the tuberosity of the base of the fifth metatarsal | plantarflexes ankle; everts foot |
| Peroneus tertius | head of the fibula and the crural ligament | by a tendon onto the head of the fifth metatarsal and on the phalanges, uniting with the tendons of extensor digitorum longus | plantarflexes ankle; everts foot |
| Note: The proximal portion of this muscle is fused with flexor digitorum longus. At its insertion on the phalanges of all the digits, the tendons of this muscle fuse with tendons of extensor digitorum longus (a muscle that shares the same insertion). | |||
| Peroneus quartus | fibula and the interosseous ligament | by a tendon onto the head of the fourth metatarsal | plantarflexes ankle; everts foot |
| Note: The proximal portion of this muscle is fused with peroneus
brevis and flexor digitorum longus. |
|||
|
Flexors (the following six muscles): |
|||
| Gastrocnemius | (1) the lateral portion: lateral condyles of tibia and femur and sesamoid of femur | through the Achilles' tendon | plantarflexes ankle; flexes leg at knee joint |
| (2) the medial portion: the medial condyle and sesamoid of femur | through the Achilles' tendon | plantarflexes ankle; flexes leg at knee joint | |
| Plantaris | lateral condyle and sesamoid of the femur | by a tendon, that separates into four parts, onto the second phalanges of the second through fifth digits | plantarflexes ankle; flexes leg at knee joint |
| Note: This muscle travels from its origin over the heel to
the plantar surface of the foot and then it divides into four parts and inserts on the second phalanges of the second through fifth digits. At the end of each tendon, immediately before insertion, they perforate to allow the passing through of the tendons of flexor digitorum longus heading toward their insertion. |
|||
| Soleus | by a tendon from the fibula head | by a tendon onto the anterior surface of the tuber calcanei | plantarflexes ankle |
| Note: This muscle's tendon, going toward the insertion, is
covered by the plantaris muscle. |
|||
| Flexor digitorum longus | lateral condyle of the tibia and the head of the fibula | by a tendon, that separates into four parts, onto the ungual phalanges of the second through fifth digits | flexes second through fifth digits; plantarflexes ankle |
| Extensor hallucis longus (tibialis posterior) | medial condyle and anteromedial surface of the tibia | by tendons, that unite with the first tendons of extensor digitorum longus, onto the basal phalanx of each digit | plantarflexes ankle and inverts foot |
| Rotator: | |||
| Popliteus | lateral condyle of the femur | by a tendon onto the proximal posteromedial angle of the tibia |
flexes knee |
To reveal the muscles of the leg, one has to continue to remove the skin from the thigh down the leg. You then have to do careful cutting with a scapula to remove the fur and skin from the dorsal and plantar surfaces of the foot. The fascia covering the leg muscles is easy to remove. The muscles of the leg can be identified in the compartments: anterior/medial, lateral, and posterior. The superficial muscles of the anterior compartment are first identified. The most anterior is tibialis anterior, and posterior to this muscle is extensor digitorum longus. Extensor digitorum longus travels down the anterior surface of the leg and across the dorsal surface of the foot before inserting onto the phalanges of all the digits. However, to better follow the tendon of this muscle down the leg, one has to cut through two retinaculi. The first one being the most superior is the crural retinaculum. It is rather tough, but can be easily cut through with a scapula and carefulness. The second retinaculum is the tarsal retinaculum. It is much tougher than the first; however, it can be cut through with a scapula, strength, and carefulness. Then turning the leg to its medial surface, one can identify the most superficial muscle is extensor digiti II, and superior to this muscle the popliteus can be seen. [See figure].
Then turning the leg to its lateral surface, one can be begin to identify the peroneus muscles. The most superficial is peroneus longus. Probing under peroneus longus, you can see the other three peroneus muscles (peroneus brevis, peroneus teritus, and peroneus quartus) cannot be easily differentiated from one another; however, their tendons can be differentiated. Due to the fusing of the three peroneus muscles, a description of their location to one another is difficult to record even though you can differentiate their tendons. Probing (or cutting the tendons of these muscles from their origin and reflecting them back) further under the peroneus muscles, one can then identify extensor digitorium lateralis running directly deep to them. [See figure]. One can follow the tendon of the peroneus longus tendon down the lateral surface of the leg and then under to the foot across the plantar surface to its insertion.
Turning the leg to its posterior surface, one can be begin to identify the superficial muscles of this region. The most superficial is the gastrocnemius; it has two heads, a medial and a lateral, that are fused together toward the edges. However, one can still differentiate them from one another. If you follow the tendons of gastrocnemius down the posterior surface of the leg to its insertion into the Achilles' tendon, you observe a third tendon. If you follow this tendon back up the posterior surface of the leg, it will lead you to the soleus. The soleus is fused with the both heads of the gastrocnemius; however, one can still identify it from the two heads of the gastrocnemius. The plantaris can be found partially covering a portion of the soleus tendon. By cutting the tendons of gastrocnemius and soleus from its insertion and reflecting these two muscles back, one can reveal flexor digitorum longus. One can follow the tendon of flexor digitorum longus running down the posterior surface of the leg and then medially along the side of the calcaneal tuber (the insertion of the tendons of gastrocnemius and soleus); it then reaches the plantar surface of the foot where it then separates into four parts and then travels across the plantar surface of the foot to its insertions onto the ungual phalanges of the second through fifth digits. [See figure].
Before dissecting into the ankle joint, once can observe that there is not a lot of movement allowed in this region of the posterior limb. When dissecting into the ankle joint, cutting tendons and just cleaning up the area, one can observe that there is indeed not a lot of movement in the joints. From moving the foot, one finds that there is a fair amount of motion allowed in the tibiotalar joint, which allows the foot to be plantarflexed and dorsiflexed. This is understandable, because this is a key motion of the foot when the rabbit is locomoting via hopping or leaping. When the rabbit's foot hits the ground it is in a slight dorsiflexed position and it is in an even more dorsiflexed position when the rabbit is about to take off. While the rabbit is in mid-leap, the foot is an extreme plantarflexed position. In the subtalar joint, there is less movement; this joint allows inversion and eversion of the foot. In the calcaneo-cuboid joint, there is no movement; this is the joint that allows the pronation and supination of the foot.
Information about the origins and insertions of the muscles was provided by
Craigie.
Information about the actions of the muscles was provided by Agur&Lee.
to Comparative Mammalian Anatomy home